ADO Relate 2 tables by more then one field

Introduction

The way to stablish a System.Data.DataRelation betwin 2 System.Data.DataTable's by 2 or more System.Data.datacolumn's.

In this example u must asume the existence of 2 DataTables in the DS_Geral DataSet with the acording fields ...

Sub Ex()
Dim DR_Afectacao_Producao as System.Data.DataRelation

Dim Parent (1) as System.Data.datacolumn
Dim Child (1) as System.Data.datacolumn
'This arrays of datacolumns must be delimited by the number of fields 
'conected in the relation, 
'thei are 0-based

       Parent (0) = DT_Afectacao.Columns("id_prod") 'The parent Table 
       Parent (1) = DT_Afectacao.Columns("id_xnuc") 'The parent Table
       Child (0) = DT_Producao.Columns("id_prod") 'The child Table
       Child (1) = DT_Producao.Columns("id_xnuc") 'The child Table


DR_Afectacao_Producao =  new Datarelation ("Afect_Producao", Parent, Child, _
                                             false )
DS_Geral.Relations.Add(DR_Afectacao_Producao)
End Sub

Example 1 Geting the Child Rows:

Dim ChildRows_1(), foundRow As DataRow

foundRow = DT_Afectacao.Rows.Find(Sender.Selecteditem.value)
ChildRows_1 = foundRow.GetChildRows("Afect_Producao")

Result:  ChildRows_1 is an Array of all of the child Rows ...

Example 2 Geting the Parent row:

Dim founded_ParentRow , foundRow As DataRow

foundRow = DT_Producao.Rows.Find(Sender.Selecteditem.value)
founded_ParentRow = foundRow.GetParentRow("Afect_Producao")

Result: foundParentRow is a DataRow in the parent DataTable of the relation ...

Summary:

The  "Rows.Find"  only finds key-values ... in the key-column of the DataTable